Tightening means for the compression and suction chambers of rotary piston engines



Aprll 2, 1935. E. KETTERER 1,996,620

TIGHTENING MEANS FOR THE COMPRESSION AND SUCTION CHAMBERS OF ROTARY PISTON ENGINES Filed 001;. 15. 1952 :5 Sheets-Sheet 1 J14 l/erz for; J 0 wm Apnl 2, 1935. E. KETTERER 1,996,620

TIGHTENING MEANS FOR THE COMPRESSION AND SUCTION CHAMBERS OF ROTARY PISTON ENGINES Filed Oct. 15, 1952 s Sheets-Sheet 2 59 l I H l "35 F7949 Fig f 2 (MI? for April 2, 1935. r E KETTERER 1,996,620

TIGHTENING MEANS FOR THE COMPRESSION AND SUCTION CHAMBERS OF ROTARY PISTON ENGINES Filed Oct. 15, 1952 5 Sheets-Sheet 3 ma \k M J m van for 44 ff m era'trices of the inne Patented Apr. 2, 1

*i'rso STA E TIGHTENING MEANS FOR'THE COMPRES- SION AND SUCTION CHAMBERS 'OF ROTARY PISTON ENGINES f Eugen Kett'erer, Essen,

half to Herman 'Germaumas'signor of one- Reis, Essen, Germany Application October 15, 1932, Serial No.

In- Germany October19, 1931 7 6 Claims. (Cl.'103123) The invention relates to rotary piston engines in which in a cylinder space a cylindrical piston of smaller diameter is moved in; a manner such as to touch by its periphery successively'the genr surface of the cylinder and in this way the space formed between the'piston and the inner surface of the cylinder and having a sickle-shaped cross section travels round the axis of the cylinder space.

By means of slides mounted in the cylinder casing and adapted to slide radially to the cylinder axis the travelling sickle-shaped space is subdivided into chambers which according to the mode of use of the engine I serve to suck, expel, compress or expand the worln'ng agent used, such as air, gas, steam or liquid.

The eificiency of rotary piston: engines of this class depends to ahigh extent upon the effect of the tightening means provided between the compression and suction the manner in which relatively to the rotary chambers, that is, upon the slides are tightened piston and to the cylinder casing on the one hand, and the rotary piston:

relatively, to the cylinder casing on the other.

: hand.

As to the slides, it is known to make use. of," in

seals of this type, a plurality of spring-influenced tightening bars arranged the rotary piston. It is a plurality of tightening bars by means of one common pressure member.

in parallel to the axis of further known to urge In these known ar rangements the provision of sufficiently strong springs for the individual tightening bars is diificult, due to the small space I the sole pressure member is provided for all tightening bars, the seal grows worse by the individual tightening bars wearing in different degree.

As the seal of the chambers on-the front surface of the piston is concerned, it hasbeen pro- I posed to provide packin nular chambers of the pressed on the side walls g rings lodged in outer anpiston v and resiliently of the cylinder. In this arrangement too, however, the'degree of tightening is not sufiicient for high esoperating under high- 'pressors and other engin pressure compressure, as the pressureisequalized along the lateral surface of the packing larly also in the spaces faces, from the compression bers.

In order to eliminate these drawbacks, the

rings andparticu within their inner surmutual sealing of the suction and compression chambers is eifected according to the invention-by phery of the piston inat disposal, and, if

to the suction chamslides being resiliently vlded on the front surfaces of thep'i'ston are: s acted upon by spring-actuated pressure pistons' which are sealinglymounted in the rotary pistonand subdivide the space behind the 'packing2rings' into separate chambers. 4

In the drawings are illustratedbyway pf ex- 10' ample an embodiment of the inventionas Iap-' plied to a double-acting rotary piston compressor, andmore particularly'show- I Fig. 1 a sectional lateral view of the'compressor, Fig, 2 a top view thereof,;as section onatheline II;;II of Fig. l,v V Fig. 3adetail of the slide onenlargedscale and in: section on the line IIIIII of Fig. 5, I

Fig; 4 asimilar view of the slide in section on-v the linelV IVof Fig. 5,

Fig. 5- a section of the of Fig. 3, r

; Fig- 6 an end view of I 20 slide onthe line V- V I the slide; seen fIfOlII lZhB'f left Fig. 3, inwhich" the tightening'bars-are" withdrawn, 3 I

Fig. 7 a top view of thestructure showndnFigs-r 3 and 4. in 'wh-ich-partcof the tightening barsis withdrawn, v Fig. 8 a detail View of a-tighteningbar, Fig.9 an end view of; a tightening-member for theends of the slide, v

Fig. 10 a-section on the line X-X offFig; 9; Fig. ll a partial end view of the'rotary-piston, Fig.--12- asection on the line XII -IHI- of Fig. lland l Fig. 1-3 asection on the line XIII-XIII 'of Flgyll". I Coaxially with thejcylinder space l--'(Figure 1) of. the cylinder casing Zsurrounded by'a cooling chamber '3 is mounted for rotation a shaft 4 in side walls 5; 6- (Figure 2)= that laterally seal the cylinder space 'I. The shafti hasinthecenter an ,eccentricprojection- 1 on which the rotary 1 piston 8 islooselyrevolubly mounted. The latter is sealed on its front sides relativelyjto the'side walls 5; 6=; In thecylinder casing 2 are arranged so as to move in the central planeof theaxis '9 (Figure 1-) of the:sha-ft 4 two slides H, "which by their piston-sealing surfaces I3 abut against the periphery of the rotary piston 8, their per manent contact with the rotary piston 8 being secured by two systems of rods M, 15, I6; I 1 attachedtotheir ends. 1 y As will be seen f-romFigurejl, the slides H and; I 2, which serve-to subdivide the sickle-shaped space formed between the rotary piston 8 and the inner surface of the cylinder l into suction and compression chambers 21, 28, 29, simultaneously control the air feeds to the spaces that just are suction chambers, by channels l8, open to the outer air and formedin the cylinder case ing, opening into recesses I9 of the slides H and 12, respectively, the inner edges 2| of which recesses in co-operation with the adjacent edges 22 of the inner surface of the cylinder form, with corresponding inward motion of the slides, inlet ports for the air to be sucked. Near the upperside of the slide II and near the underside of the'slide I2 is provided each a pressure valve 23 and 24, respectively (Figure 1), from which a pipe 25 leads to the pressure container (not shown).

The tightening arrangement of the slides relatively to the rotary piston and the cylinder casing, forming the subject-matter of the invention, will now be described in detail withreference to Figures 3 to 10. As will be seen from the end .view of the slide according to Figure 6, the piston-sealing surface 13 of the slide and also a part of the two ends'of the slide is provided with four through-going grooves 3! obtained by two notches with a rib 32 therebetween and by two thinintermediate. sheet metal plates 33. The latter are fixed to the body of the slide by pins 2 34 (Figures 3, 4, 6). Each of the grooves is filled byja two-part tightening bar 35 and by a pressure bar 35.-

The shape of one half of tightening bar is to be seen from Figure 8. It possesses on one end a rectangularly bent extension 31 by which the seal on the front sides of the slide is effected, andon the other end an oifset 3B in which engages the correspondingly offset end of the other half of the tightening bar. The two halves of the tightening bar completely conform with one another in shape and size so that they maybe replaced and exchanged at will. The pressure bars 35(Figures 3, 4) engage by their ends in recesses 39 of the tightening bars 35 in such a manner as .to permanently remain by their outer narrow surface in" close contact with the tightening bars 35. Each pressure tensions 4| by which it pro ects into the interior of the slide'body.

In the slide are provided four spring chambers 42, 43, 44, and 45. In each of these chambers is slidably mounted a pressure piston 4'! in a bore of which is lodged a compression spring 46. On its-top end each pressure piston 41 has a semicylindrical cavity 48 (Figures 4, 5) in which loosely rests a semi-cylindrical pressure piece 49. With the plane top surface of these pressure pieces are in contact the above-mentioned extensions M of the pressure bars 36, each of the pressure pieces 49 acting upon two pressure bars 36 arranged equidistantly to its turning axis in such a manner that the pressure exerted by the spring 46 is uniformly distributed on the two pressure bars 36 and thus to the tightening bar 35influenced by the latter.

As will be seen from Figure 5, the pressure pieces 49 of the spring chambers 42 and 45 act upon the two outer pressure bars 36, whilst the pressure pieces .49 of the spring chambers '43, 44 actuate the two inner-pressure bars 36'. From Figure '7, in which part of the pressure bars and tightening barsare withdrawn, is clearly r 7 various extensions 41. As will be seen, the influence by pressure of the variagainst the tightening this contact by the recesses 39, the various openbar 36 further possesses two ex ous tightening bars 35 is such that each tightening bar may abut against the rotary piston independently of the other.

The division of the tightening bars into two parts is required by the end tightening means of the slide hereinafter described. As a consequence of this division, however, more or less great passage openings occur on the overlapping places, which may allow leakage of the working agent. The object proper of the pressure bars 36 is to prevent this, leakage. By the fact that they abut by their upper narrow surfaces closely bars 35 and are held in ings on the overlapping places are prevented from entering into communication with one another through the space existing below the bars 35. If this tightening of the overlapping places were not required, the pressure bars 36 could be omitted, if the extensions 4| were provided irmnediately on the tightening bars 35.

As already mentioned, the seal of the slide on the ends is effected by the extensions 31 of the tightening bars 35. These extensions are acted upon by apressure piece 52 (Figure 3) which ter-f minates in a bolt 54 surrounded by a spring 53. The latter abuts on an inner surface 55 of the slide body-and presses the four extensions 3'! of the respective slide end simultaneously against the inner surface of the side wall 5 or 6 of the cylinder (Figure 2).

In order to seal also the passages formed between the extensions 3?, a special sealing member 56 (Figure 3, 6, 9 and is provided which, as will be seen from Figure 6, occupies the whole width of the end of the slide and has recesses 51 and slots 58 (Figure 9) into which sealingly project the extensions 31- and, respectively, the intermediate sheet/metal plates 33.. The sealing member 56 is shiftably mounted in a corresponding space'59 (Figure 3) of the slide body; 56 is hollow and carries the above-mentioned pressure piece 52 ina smallerrectangular cavity 6| (Figures 3-10), which, as to be seen from Figure 10, is open toward the recesses 51, while an enlarged cavity 62 guides a compression spring 63 which surrounds the spring 53 and likewise abuts against the surface 55 of the slide so as to sealingly press the front side of the sealing member 56 against the side walls 5 and 6, respectively, independently of the extensions 31. It will be seen that in this'way the compression and suction chambers pairtioned off by one slide ll, I2 are perfectly tightened relatively to the end of the slide.

During the reciprocating motion of the slides H and I2 notable inertia'eifects occur in consequenceof'the comparatively high rate of revolution of the shaft'4-of about 1000 R. P. M. which effects cause theslides to move beyond the dead position determined by the eccentricity of the eccentric i (Figure 1) and to elastically influence also'the rotary piston B-in such a manner that it tends to enter the slide space of the cylinder casing andupon further motion strikes against the edge22 (Figure 1). In order to overcompressor, a further packing 65 66, II (Figures- 3, 4, and 6) of known construction is provided on each slide 1 I, I2 by which the space denoted by 64 in Figure Lthat is the space behind the slide; is sealed outwardly. In this way, owing to the compression of the air contained therein,

this space acts as a cushion when the slide moves cause damaging ofthe piston V In the following will now-2be described in de tail the'sealing of the endsof the rotarypiston withreference to Figures 11-13. on each piston side is arranged an" annular channel 9-I which hasmounted in itone or more metallic packing rings 92, 93. On the righthand side then follows an annularpacking disc 94 (Figures 12 and 13), and then two spring rings 95," 96, one of which is resilient in outward directionwhile the other is resilient in inward direction. The two spring ringsmay' be disposed side-by sideor, as illustrated, in 'the'sameplane." Then follows another annular packing 1 disc 91' and, further, a pressure ring 96, preferably made from steel. The pressure ring 98' is acted upon byequidistantly arranged pressure" pistons 99 (Figures 11, 12) which are tightly mounted in corresponding bores of the rotary piston 8 and on their offset inner ends IOI' (Figure 12) carry compression springs I02 that abut against the partition I03 of the hub of the rotary piston. As will be seen, the packing rings 92, 93 are pressed in this way uniformly onto the side wall of the cylinder and any passage happening to exist between their peripheral surfaces and the annular channel 9| is efi'icaciously tightened by the two spring rings 95, 96 and the annular packing ring 94 Suitably the outer packing ring is provided with a crown of teeth I 04 (Figures 11 and 12), which engage in a corresponding crown of teeth I05 provided on the outer part of the rotary piston.

The tightening pressure of the two packing rings 92, 93 has to be particularly strong in those parts of the rings which just are in the range of the compression chambers (chamber 21, Figure 1), whilst for the remaining parts of the rings the tightening pressure may be correspondingly smaller. In order to obtain such a different distribution of the pressure, the pressure itself prevailing in the compression chambers is used to contribute to the tightening pressure by being led behind the packing rings 92, 93. To this end the outer packing rings 92, the outer spring ring 95, the annular packing discs 94, 91, and the pressure ring 98 are provided with bores I06, as to be seen from Figure 13. If that part of the packing ring 92 which is in the range of a compression chamber, is not sufiiciently pressed against the side wall of the cylinder, the more or less throttled pressure prevailing in the compression chamber is thus capable of entering between this ring part and the side wall ofthe cylinder in the bore I06 and spreading out behind the pressure ring 98 in the space III! of the annular channel 9|. The consequence thereof is that a supplemental pressure is added on the respective place to the invariable tightening pressure of the springs I02 by which the complete tightening is obtained with security.

It has now to be avoided that the pressure entering from the compression chamber in the space I01 be distributed on the whole annular spaceil 01 :since it has: to :act; as explained; onlthbsei parts of'theapacking rings: which just are the range of? the compression .shambers. To. this -end. the space I01 is subdividedlinto individual' chambers which are sealed relativelyto one another, andthis isiefiectedaimmediately by the pressure'pistons 99 (Figure 12) the diameter of.which exactly/corresponds to the heightcof the annular channel 9II. According to: Figures .1 and 11 six such pressurepistons 99 are provided which between 'themselvesiform six: 'sepa rate'ichambers of the space I01. Inpractic'eonewill. increase as possible the number of thepis-' to :conveniently: and: securely feed the pressure to the bores I06, the latter open into open' channels I08 thelocationandlength of which:correspond to the chambers 'of the spaceI 0-1.:

The excellent efiiciency of th'e described tighteningarrangementior the sides of the rotary piston-is due primarily to'the subdivision of the spacecllll rexistingbehind the pressure ring 98,

into. indivdual chambers, as wellas due to the co-operation of the pressure ofthe working agent for urging thetightening rings on'tothe 'cyl-' inder' side wall. It. is evident that these main effects are obtained also, if, in order-to simpIify the arrangement, instead of the members 92-98 one sole packing ring with bores I06 and corresponding open channels I08 is arranged in the tons and thereby that of th'echambers In order annular channel and is pressed directly onto the cylinder wall by the pistons 99. Obviously, several such simplified packing rings may be provided on each piston end, concentrically to one another. I

I claim:

1. In an engine of the class described a cylinder casing, a rotary piston rolling in'said casing,

a slide shiftably mounted in said casing and dividing the space existing between said piston and. easing into compression and suction chambers, a plurality of tightening bars shiftably mounted in said slide and adapted to co-operate with the periphery of fixed in said slide and separating the tightening bars from each other, said tightening bars being arranged in pairs, the bars of the pairs overlapping one another, pressure pieces adapted to act each upon the two tightening bars of each pair and having semi-cylindrical shape, pressure pistons shiftably' mounted in said slide and formed on their outer ends with cavities receiving the semi-cylindrical surfacesof said pres! sure pieces, and spring members adapted to act upon said pressure pieces in the middle between their points of action upon said bars and adapted to urge the latter independently of one another onto said piston. V

2. In anrengine of the class described a cylinder casing, a rotary piston rolling in said casing, a slide shiftably mounted in said casing and dividing the space existing between said piston and casing into compression and suction chambers, a plurality of tightening bars shiitably mounted in said'slide and adapted to co-operate with the periphery of said piston, spring-influenced 'pres sure pieces adapted to act upon said tightening bars, a pressure bar belonging to each tightening bar and arranged between the pressure pieces and-the inner edge of the respective tightening said piston, partitions I andcasinginto compression and suction chambers, a plurality of tightening bars shiftably mounted in said slide and-adapted to co-operate with the periphery of said piston,' spring-in fluenced pressure pieces adapted to act upon said tightening bars, the latter being subdivided, inner recesses on their ends, a pressure bar arrangedbetween said subdivided tightening bars and said'pressure piecesand engaging by its ends in said recesses. V 4, In an engine of the class described, a-cylinder casing, -a' rotary pistonrolling in said 035- ing, a slide shiftably mounted in said casing" and dividing the space ,existingbetween said piston and casing into compression and suction.cham-' bers, a plurality of tightening bars shiftably mountedin said slideand adapted to co-op'erate with theiperiphery, of said piston, said tightening bars being subdivided, a rectangularly bent extension on the .end of each tightening .bar, a spring adapted to urge the extension against .the side wall of, said cylinder, a' sealing 'membershiftablymounted at each endoisaid slide,"slots in-said sealing member adapted to be engaged by said extensions, ribs on said;- sealing member formed by said slots and sealinglyt filling the intermediate spaces between said extensions, and

a second spring adapted to urge the sealing member against the side wall of said cylinder.

5. In an engine as specified in claim 4 a hollowspace in. said sealing member, an. ofiset therein, a. compression spring adapted to act upon said ofiset, another compression spring arranged concentricallyto the former and adapted to act upon the extensions of said tightening bars.

6. Invan engine of the class described a cylinder casing, a rotary piston rolling in said casing, a slide shiftably mounted in said casing and dividing the space existing between said piston and casing into compression and suction chambers, a; plurality of tightening bars shiftably mounted :in said slide and adapted to co-operate with the periphery of said piston, an annular channel on the end surface of said rotary piston, packingringsin said channel, spring-influenced pressure pistons shiftable in the direction of the axis oi; said rotary piston and adapted to urge said packing rings onto the side wallsof said cy1inder, sealingmeans between said pressure pistons and the walls of said channel whereby the space existing behind said packing rings is subdivided into separate chambers.

,- EUGEN KETTERER. 

